China will send 16 naval ships and two submarines to its first joint naval exercise with Russia, slated to start this weekend in the Yellow Sea, the Ministry of National Defense said on Tuesday.

The drill, which Russian authorities said will involve warships cruising near Japanese waters, has rattled the nerves of media from Japan and South Korea.

Japanese media speculated that the move is aimed at warning Japan, which has maritime disputes with both China and Russia, while Seoul-based Yonhap News Agency said its coincidence with a joint drill between South Korea and the United States is a showcase of military muscle that can balance the US in the region.

However, Major General Qian Lihua, director of the Foreign Affairs Office with the National Defense Ministry, told Chinese media on Tuesday it is “normal arrangement” within the framework of military cooperation between Beijing and Moscow, adding that the drill was decided last year.

Since 2005, China and Russia have conducted several joint military exercises within the framework of the Shanghai Cooperation Organization, which also includes the Central Asian countries of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.

Still, as the first joint naval drill between the two Asia-Pacific powers, the exercise bears great significance, Chief of the General Staffs of the People’s Liberation Army Chen Bingde told his Russia counterpart on Tuesday.

“The joint exercise will lift the level of strategic cooperation and mutual trust of the two militaries and boost the capability of the two navies to jointly handle new threats and challenges in the region,” the general said, according to a news release from the Defense Ministry.

Rear Admiral Leonid Sukhanov, the Russian navy’s deputy chief of staff who will lead the drill with Ding Yiping, deputy commander of the PLA Navy, has said the exercise will provide a “good test” for the two armed forces.

The drill will focus on the protection of key maritime arteries and cover several phases including a maritime military review, according to Qian.

He said China will send 16 naval ships, including destroyers, frigates and missile boats, to the Yellow Sea near Qingdao, a coastal city in Shandong province where the headquarters of the Chinese North Sea Fleet is located.

Xinhua reported earlier that four warships from Russia’s Pacific Fleet left Vladivostok to participate in the exercise, which is scheduled to conclude on April 27.